1. Field of the Invention
The invention relates to an electrostatic discharge (ESD) protection circuit, and more particularly to an ESD protection circuit for a low-voltage process.
2. Description of the Related Art
Electrostatic discharge phenomena will cause damage to semiconductor devices and affect the normal functioning of integrated circuits (IC). Thus, it is a necessary goal for IC designers, during the design stage, to enhance ESD protection of an IC to increase ESD sensitivity.
Recently, more and more ICs can operate with lower operating voltages, such as operating voltages of typical logic circuits, i.e. 1.8V etc., due to the rapid advancement of low-voltage manufacturing technology. However, for certain products which have particular application requirements, certain pins for an IC require operating at higher voltages, i.e. 3V, 3.3V and so on.
For ICs, malfunctions will occur in low-voltage devices when a higher voltage is applied to the low-voltage devices. In this situation, the functions of the low-voltage device will be false since the low-voltage ESD protection circuit is unable to protect pins operating at higher voltages.